Control arrangement for a working cylinder

Abstract

In a control arrangement for a working cylinder ( 1 ), which may be actuated by a pressure medium, there are provided two separate adjustable regulating valves ( 4, 5 ) for both sides of the cylinders, each connected with a pressure medium outlet (t) on one side and with the working cylinder ( 1 ) on the other side. The adjustment elements ( 4′, 5 ′) of the two regulating valves ( 4, 5 ) are housed in a common valve housing ( 31 ) for simplification of production, connection, assembly and maintenance; whereby the valve housing is provided with pressure medium connections for both cylinder sides that are to be controlled and with the corresponding conduits.

I claim:  
     
       1. A control device for separately and independently controlling two flows of pressure medium to a working cylinder, said control device comprising: 
       a housing which defines first and second opposite ends, a passageway therethrough, first and second pressure medium inlet connections, first and second pressure medium outlet connections, a pressure medium discharge connection, and a first and second pressure chambers located at said opposite ends,  
       first and second independently movable adjustment elements which are located in said passageway and always define a gap therebetween to assure independent movement thereof, there being no mechanical means attaching said first and second adjustment elements together across said gap, said first and second adjustment elements defining fluid passageways therethrough to communicate said respective first and second pressure chambers with each other and a prestressed check valve for controlling pressure medium flow from said first and second pressure medium chambers to said pressure discharge connection, said first and second pressure chambers becoming pressurized with pressure medium leaking past said respective first and second adjustment elements, each of said first and second adjustment elements defining two control edges which respectively and independently control flow of medium inlet connections to said first and second pressure medium inlet connections to said first and second pressure medium outlet connections depending on independent axial positioning thereof within said housing, and  
       first and second drive means at said first and second ends of said housing respectively connected to said first and second adjustment elements to control movement thereof within said housing independently of one another.  
     
     
       2. A control device according to  claim 1 , wherein said first and second adjustment elements respectively comprise first and second pistons. 
     
     
       3. A control device according to  claim 2 , wherein said first and second pistons are coaxially positioned within said housing and define axial bores therethrough which enable pressure medium to flow from said first and second pressure chambers to said pressure medium discharge connection. 
     
     
       4. A control device according to  claim 3 , including a control sleeve located within said housing between said first and second pistons and an interior wall of said housing. 
     
     
       5. A control device according to  claim 4 , wherein said control sleeve comprises separated first and second sleeve parts which are respectively positioned between said first and second pistons and said interior wall of said housing, and wherein said valve comprises a prestressed elastic sealing ring positioned around a gap defined between adjacent ends of said first and second sleeve parts, said elastic sealing ring being movable to open said opening with sufficient fluid medium pressure applied thereto through said axial bores so as to enable pressure medium flow to said discharge connection.